Although significant progress has been made in describing a variety of secretory systems and some information is available regarding secretory dysfunction in disease, the actual molecular events and cellular regulatory mechanisms involved in cell differentiation, gene expression, growth and secretion and the actual molecular events that occur in the dysfunction of salivary gland cells are still poorly understood. The development of procedures for the primary culture of salivary gland cells under serum free conditions and the establishment of permanent cell lines of specific salivary gland cells would greatly enhance ones ability to study the actual molecular events involved in normal salivary gland function and it would also permit, under more controlled conditions, the study of salivary gland dysfunction in disease. We are proposing to continue our current research efforts to establish serum-free primary culture procedures for rat submandibular and parotid cells. Detailed morphological, physiological, pharmacological and biochemical analysis will be used to evaluate the cells while in primary culture and to assess cytodifferentiation. In addition, given the fact that we characterized the rat submandibular and parotid acinar cells general growth and survival requirements, it is now also feasible to initiate procedures for the establishment of continuous cell lines for these cells. We plan to establish "immortalized" cell lines via transfection with specific plasmids containing specific viral constructs. The cell lines will be characterized after transfection, low passage, during crisis and immortalization. The same morphological, physiological, ultrastructural and biochemical procedures will be performed on these cells as in the serum-free primary culture studies.